This is a report of research conducted in 1930-31 in the geological laboratory of the University of Wisconsin as a project of the American Petroleum Institute. Results of previous studies on the generation of oil in rocks by shearing pressures have been published in earlier numbers of this Bulletin. Those earlier phases of the work have shown that slightly larger amounts of soluble organic matter may be extracted from shales that have been subjected to shearing pressures at room temperature than can be recovered from unsheared samples of the same materials. The conclusion was reached that, though the change in the amount of extractable organic matter is quantitatively unimportant and may ordinarily be related to physical causes, the effect can not be neglected. Subsequent attempts to discover the effects of shearing pressures on the same materials at temperatures existing at depths of oil accumulation produced conflicting results. The amount of “soluble bitumen” recoverable from samples so treated was less than that from untreated samples. In general, however, the results confirm the observations of other workers. The character and the amount of the products formed by the action of heat on the organic matter of this shale are found to depend on the combined influence of three variable factors: temperature, duration of heating, and the ratio between the volume of organic material and the volume of pore space available to the gases generated as a result of heating.